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Revolutionising atomic clocks

The clock's tick is derived from the interaction between the laser and the atom trapped in the heart of the atomic clock

Researchers from the Centre for Quantum Technologies (CQT) at NUS have discovered that lutetium — a previously overlooked element — possesses properties ideal for making high performance atomic clocks. This could pave the way for the construction of next generation atomic clocks that are more accurate and stable over time.

In atomic clocks, time is measured using the oscillations of a laser light wave tuned to a specific frequency matching that of the atom in the clock. Atomic clocks have set the global standard for measuring time for over half a century.

Assoc Prof Barrett (left) and Research Fellow Dr Kyle Arnold from CQT realised the potential of adopting lutetium in building high performance atomic clocks

Currently, caesium, another element, is used in the atomic clocks which support the Global Positioning System and synchronise transport and communication networks. However, there is worldwide competition to adopt other elements such as ytterbium, aluminium and strontium to improve the accuracy and stability of atomic clocks.

The ultimate performance of a clock comes down to the properties of the atom — how insensitive the atom is to its environment. I would call lutetium top in its class.

— Assoc Prof Murray Barrett, Centre for Quantum Technologies

The discovery of lutetium is therefore timely. A lutetium clock ticks some ten thousand times faster than a caesium clock, allowing it to make more precise measurements of time. It is also the least sensitive to temperature among all established atomic clocks, making it highly stable.

Associate Professor Murray Barrett who led the research said, “The ultimate performance of a clock comes down to the properties of the atom — how insensitive the atom is to its environment. I would call lutetium top in its class.”

A novel ‘hyperfine averaging technique’ invented by Assoc Prof Barrett and his collaborators that cancels out certain sources of inaccuracy enabled the team to realise the potential of adopting lutetium in atomic clocks. This technique could one day be employed to build high-performing lutetium clocks that can operate in a wider range of environments.